Imaging devices—including scanners, copiers, facsimile machines, multifunction printers, all-in-one devices, or other devices—convert physical objects (e.g., documents, photographs, etc.) into electronic data. In some examples, imaging devices can include an automatic document feeder (ADFs) to receive stacks of media to provide to a scanner sub-assembly for imaging. ADFs may utilize a transmission having a series of motors and rollers to transport the media between trays.